COP26 is over, and the results are not exactly pleasing to those of us who wanted some radical change in fighting climate change. The pledges made in Paris in 2015 are being left behind. The best steps taken to get rid of atmospheric carbon are not being actively pursued – and the ones that are pursued are costly and less effective.
CNN published an article about the new carbon capture plant in Iceland, the largest direct air capture device presently online, and labeled it a “big risk.” (“The world is banking on giant carbon-sucking fans to clean our climate mess. It’s a big risk.”). The plant, touted as the world’s largest, “opened [in September 2021] and currently removes about 10 metric tons of CO2 every day, which is roughly the same amount of carbon emitted by 800 cars a day in the US. It’s also about the same amount of carbon 500 trees could soak up in a year.”
Direct Air Capture is one of the big hopes for bringing carbon in the air down to an acceptable level. The top ten carbon capture options are said to be the following:
1. Planting trees – afforestation and reforestation
2. Bioenergy with carbon capture and storage (BECCS)
3. Direct Air Capture (DAC)
4. Habitat Restoration – Blue Carbon
5. Building with Biomass
6. Biochar
7. Soil Carbon Sequestration
8. Enhanced Weathering
9. Enhanced Ocean Productivity
10. Increasing Ocean Alkalinity
First, none of these options provides the “silver bullet” to combat climate change. In combination a number of these options could make a significant impact.
Planting trees is the easiest way of sequestering CO2. However, it is a slow process and availability of land a limiting factor.
BECCS looks promising and its “double gain” makes it a good option for biomass fuelled power stations. It should be possible to apply the same technologies to other CO2 emitting industries.
Direct Air Capture (DAC) looks to be impractical, as to make a difference the amount of energy required is huge. That said, under certain circumstances it might become more practical. Look out for our forthcoming blog, “Why Direct Air Capture might just work”.
Building with Biomass will require both industry and government action to make it mainstream. Even then it will only ever be a part of the solution.
Habitat Restoration in the form of Blue Carbon, although less relevant globally, could make a significant contribution to carbon capture on a national scale. Countries like Bangladesh, Colombia and Nigeria would benefit considerably by improving conservation and restoration of their marine ecosystems. They could either use the carbon sequestered to balance their own emissions or sell as carbon credits to other countries, which could be a source of income.
Soil Carbon Sequestration sound a good idea, but recent research still indicates that the effects could be marginal and “[the way to minimize the impact of] agriculture is to stop clearing more land.”
The exploitation of Biochar in the UK, and elsewhere is still hampered by a lack of formal regulation. To be fair, the Scottish Environmental Protection Agency (SEPA) has published an interim regulatory position on the use of waste. However, without formal regulation and governmental direction, development will be slow.
Enhanced Weathering is likely to remain an idea with potential, but due to cost and possible unintended consequences, it is likely to remain just that.
Enhanced Ocean Productivity is also likely to suffer the same fate as Enhanced Weathering. In addition to the cost and possible impacts on the ocean’s ecosystem, there is also the problem of international law and the UN’s attitude to geoengineering experiments. These latter two have probably sealed its fate.
Increasing Ocean Alkalinity, although likely to suffer from the issues affecting Enhanced Ocean Productivity, it might have a future if the seeding of clouds with alkali is proved to be practical. A problem could when the alkali rain falls outside the national boundaries of the state sponsoring the program. Surrounding countries may hold different views on geoengineering of this type.
If we are to achieve Net Zero by 2050 and limit global warming to 1.5°C more than one of these options will need to go beyond the trial stage. Building with Biomass and Habitat Restoration will have an increasing but limited impact. Biochar may yet garner sufficient investment. However, planting trees, BECCS and DAC (Direct Air Capture) look to be the prime contenders.
Unfortunately, even this broad look at the problem of carbon capture fails to discuss two other solutions which are relatively inexpensive and which avoid problems that trees involve. These two solutions are cultivating hemp and bamboo. Both of these grow a lot faster than trees, provide better carbon capture, and offer product uses that many of the other solutions do not offer.
“Hemp can capture atmospheric carbon twice as effectively as forests while providing carbon-negative biomaterials for architects and designers, according to Cambridge University researcher Darshil Shah. … “Industrial hemp absorbs between 8 to 15 tonnes of CO2 per hectare of cultivation.” Carbon-negative bioplastics and construction materials made from the plant can be used to “replace fibreglass composites, aluminium and other materials in a range of applications,” he added. The Icelandic carbon sucking plant can take out 10 tonnes of carbon per day. This means that 365 hectares of hemp gives around the same result as a year of DAC use. Except that the hemp can be used for other things besides taking in carbon.
Bamboo has similar positive aspects. “A mature grove of bamboo, according to numerous experts, can also generate 30 to 35 percent more oxygen than an equal area of forest. To produce this oxygen, the bamboo draws carbon dioxide from the atmosphere. The plant then stores much of that carbon in its roots and biomass.” Bamboo is also one of the fastest growing plants in the world. “As a grass, bamboo easily replenishes itself after harvesting. In other words, like a lawn that’s been cut, the bamboo grows right back. Unlike trees and annual crops which get harvested and then need to be replanted, the rhizome roots of bamboo plants live to produce more shoots. Because the bamboo doesn’t die, it doesn’t release its carbon sink the way a tree does after it’s cut down.” Bamboo is a greener alternative to lumber. “Bamboo plants have some useful properties and having lot of beneficiary uses; these are using as pillar, fencing, housing, house hold products, raw materials of crafts, pulp, paper, boards, fabrics industry, fuel, fodder etc.”
Why weren’t these plants discussed at COP26? Probably because hemp has a bad reputation of being related to marijuana, and bamboo is an enemy of wood lumber companies. But those aren’t good reasons. Fast growing plants are better than trees and cheaper than mechanical devices like DAC. The time has come to stop viewing these plants with a blind eye and start to use them in an effective way.
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